Automated document processing devices, such as sorters or inserters, are commonly used in the mail processing industry, and are often equipped with various peripheral or in-line devices that further ease the processing and distribution of mail. An example of such a device is a labeler, which may be used in conjunction with the document processing device for applying a label to a mail piece. In addition, a printer may be used in conjunction with the labeling device for applying print contents to the label before or after its application to a mail piece. Print contents on a label can be one or more lines, and will vary depending on the way in which the label is to be applied to a given mail piece. As such, different-sized labels must be generated for different applications. For basic barcode printing, the label can be set to a default value of approximately 0.5-inches tall. However, for address block printing or customized message printing, a larger label may be required ranging from about 0.5 to 1.25 inches or more height as the length of the print content increases.
As illustrated in FIG. 7, various types of labels capable of being applied to a mail piece are shown. A first label 300 is comprised of a three line address block, while a second label 302 has a six line address block. Also, a third label 304 has a barcode printed on it, while a fourth label 306 has a corporate logo printed on it. Each of labels 300, 302, 304 and 306 has a specified height, represented as H1, H2, H3 and H4 respectively. The labels 300, 302, 304, 306 may also be assigned a default label margin, Hmargin, for determining an inner perimeter for the application of print contents. For this example, it is assumed that the labels all originate from the same label roll, wherein the individual label length L of the label from each print roll is fixed (by the lateral dimension or width of the label material on the roll). Hence, variation in label height (amount of material pulled off the roll for a particular label) is generally the means by which to accommodate the varying print contents of labels 300, 302, 304, 306. As illustrated in FIG. 7, height H2, having the most print contents is of a larger size than that of height H3. In conventional mail processing environments, the various sized labels shown in FIG. 7 would be applied during separate job runs. So for instance, mailings having print contents requiring a label of height H2 would be processed during a first job run, while mailings having print contents of H4 would be applied during a second run.
Proper application of uniformly sized labels to mail pieces having uniform mail piece characteristics (e.g., height, length) is the simplest way to ensure effective labeling, especially due to the high transport speed of most document processing devices. Such uniformity allows for easier programming and cycle timing of the labeler and/or label printer. Sensors are positioned in fixed locations on a mail transport to determine mail feed and advance; to more easily allow the labeler to predict when to prepare for the next label. Such an approach is limiting however and quite impractical, particularly when different sized mail pieces having different sized label print contents must be processed during a single job run. Even when mail pieces are relatively identical, the mail gap, defined as the relative time/distance interval between mail pieces, may vary. Consequently, to overcome such challenges, mail processing facilities resort to simply applying a fixed label size to specific batches of mail. While this fulfills the labeling task, such a scheme is neither ideal nor accommodating of multiple-type mail piece processing.
As a further complication with fixed (unconditional) labeling systems, if the system misses applying a label due to erroneous peripheral performance or mail handling, the mail transport system must be stopped, and the label already fed and cut onto the label application paddle must be manually removed to prevent mislabeling of subsequent mail pieces. Failure to manually correct the mislabeling could result in the incorrect label being applied to each and every one of the subsequent mail pieces. Unfortunately, the manual resolution and overall lag time that occurs in this scenario significantly limits the throughput and efficiency capability of a high speed document processing device.
Adverting to FIG. 4(a), illustrated therein is a timing analysis diagram for a conventional label feed system. During a conventional single label feed cycle, a signal plateau 502 defines the length of a label to be applied to a mail piece. A signal acceleration phase (signal ramp up) 501, plateau phase (signal apply) 502, and deceleration phase (signal ramp down) 503 are shown in FIG. 4(a). Between the time of activation of the signal acceleration phase 501, the plateau phase and the signal deceleration phase 503, various labeling activities may occur including: actuation of the label cutter, printing of the label contents onto the label, deactuation of the cutter, activation of the label feed paddle for feeding of the label onto the mail piece, and deactivation of the label feed paddle to release the label fully onto the mail piece. To align these activities during the label feed cycle, proper timing and sequencing of events is critical.
When a label is applied in a uniform or fixed manner (e.g., according to conventional label feed cycle processing) without accounting for variances in mail gap that may occur between mail pieces, this is known as unconditional labeling. Mail gap refers to the relative time and distance relationship between mail pieces being processed by the document processing system. Since mail feed processing rates and performances may differ from one document processing system to the next, different mail gap between pieces may occur. The result is a one-size-fits-all labeling approach—an approach that does not account for differences in label sizes with respect to the contents to be printed upon the label. Consequently, when the labeler feeds and cuts a label of a certain size (even if it is of the wrong size to accommodate the print contents), the label must be applied to a document. If an incorrect-size label is fed and cut on the label application paddle, manual intervention must occur to remove the label, which means complete stoppage of the document processing system and reduction in throughput and processing efficiency.
Even when the labeling application involves uniform-size mail pieces, an incorrect-size label can still be fed and cut by the labeler due to inconsistent mail gap between documents as previously described, and different label size. Thus, even the same sized mail piece may still require a different size label to accommodate different print contents. As such, each piece will require different timing to feed and cut a label of different size for its print contents. In high-speed labeling applications, these factors combined to produce inconsistent time allowed for label feed cycles between documents in the mail processing stream.
To address the problems described above, a system is needed that can minimize if not completely eliminate the possibility of mislabeling or failing to label a mail piece requiring a label. Furthermore, a system and methodology is needed to accommodate variable sized labeling capability to support varying labeling applications for a high-speed transport system.